(1) Field of the Invention
This invention relates to agriculture and more particularly to drafted implements for cutting the roots of weeds.
(2) Description of the Prior Art
In the growing of crops, it is ordinarily desirable to prevent the growth of weeds therein. Some weeds grow from seeds, while other come up from roots. In many cases, herbicides may be used to control weeds. Unfortunately, herbicides are somewhat ineffective against root weeds. Because the roots of root weeds are deep within the soil, it is difficult to get the herbicide in contact with the weed root. It is also difficult to kill root weeds with herbicides without adversely affecting the crop as well. Bed planting, wherein soil is turned over and piled to form soil beds, serves to exacerbate the root weeds problem by concentrating such weeds in the beds.
Before my invention, rigid, horizontal, sword-like knives were ripped through the soil to cut the weed roots. As the swords were ripped through the soil, weeds, dirt, and other material tended to collect on the swords, thereby increasing the friction and disturbance of the soil. Many crops are adversely affected by such soil disturbances. The large soil friction factor resulted in a requirement for substantial amounts of draft power to drag the swords through the soil. Additionally, weeds collecting on the leading edges of the swords increase friction with the soil, and later dislodge during the movement through the soil, tending to spread the weed roots through the beds.
Another method of mechanically controlling root weeds is by shallow cultivation. Manual hoeing will cut the root weeds very close to the soil surface. Sword knife, or sweep plow, cultivators may be used with less draft power by dragging the sword knives, or sweep, iust under the soil surface, much as with hoeing. Tandem disc plows or other shallow cultivators may also be employed to cut the weed roots near the soil surface. Such shallow cultivation methods produce unacceptable soil disturbance. Additionally, the closer the weed root is to the soil surface, the sooner it will emerge and have adverse effect on the crop. Therefore, such shallow weed cultivation methods must be repeated frequently during the course of the crop growth to be minimally effective.
Before this application was filed, a search was made in the United States Patent and Trademark Office. That search developed the following United States patents:
POULE, U.S. Pat. No. 719,863 PA1 SMART, U.S. Pat. No. 804,631 PA1 BUSCH, U.S. Pat. No. 1,161,109 PA1 PSENCIK, U.S. Pat. No. 1,172,046 PA1 SCHIEL ET AL, U.S. Pat. No. 2,363,268 PA1 SCHLUETER, U.S. Pat. No. 2,651,905 PA1 ADAMS, U.S. Pat. No. 2,864,297 PA1 BEAMAN ET AL, U.S. Pat. No. 3,058,531 PA1 JOHNSON, U.S. Pat. No. Re. 9,168